Effect of Vision on Reduced Gravity Posture

In the present study, 8 experienced neutral buoyancy test divers were instructed to maintain quiet relaxed posture while ‘standing’ in instrumented space shuttle middeck (IVA) type foot restraints in the Space Systems Laboratory (SSL) Neutral Buoyancy Research Facility (NB) and onboard the NASA KC-135 reduced gravity aircraft (PF). Foot restraint reaction loads and subject joint angles were recorded during blind and sighted conditions. Visual cues played a significant role in subject anxiety onboard the KC; however, while subject joint angles and reaction loads differed between NB and PF conditions, no differences were found between sighted and blind conditions in either simulation environment for reaction loads or joint angles. This very surprising result indicates that there are not only anecdotal but concrete differences between reduced gravity and terrestrial posture mechanisms.